In a mobile communication system and especially in a cellular system, a wide communicable service area is secured by arranging a cover area of a base station whose cell radius is different from each other so that the cover areas overlap each other. However, when the cover areas of the base stations overlap each other, the signals of the base stations interfere with each other and whereby there is a risk of decrease in line capacity. Additionally, a probability of existence of the base station which has no mobile station in the cover area of the cell rises with the increase of the number of the base stations. Although such base station is not used, it continues the operation and consumes an electric power needlessly.
Therefore, a technology for avoiding interference and reducing the consumed electric power in a mobile communication system is proposed. For example, a technology in which a base station monitors a downlink signal transmitted by another base station, transmission from the base station is stopped or started by considering a traffic condition of the another base station and a received power, and whereby the number of base stations operating in a low traffic state is reduced and interference to the neighboring base station is reduced is disclosed in patent document 1.
As the related art, in patent document 2, there is described a base station resource control unit which determines whether to increase/decrease a base station wireless communication unit or maintain a current status, based on information (traffic volume and usage situation) registered in an information management table. This base station resource control unit performs ON/OFF control of supplying power to each base station wireless communication unit based on the above-mentioned determination result.
Additionally, as the related art, in patent document 3, there is described a network management device which compares current traffic information and past traffic information with subscriber terminal position information that are accumulated and stored in a traffic information database and a subscriber position information database and estimates near future traffic information required for reallocation of a network resource.
Further, as the related art, in patent document 4, there is shown that when the resource of a service is assigned, a daily average traffic trend chart in which classification is performed for each service, each weekday, holiday, or day of the week, each month, or simply, each day, or the like is held in a base station or a device for controlling the base station as data as necessary.